The Earth *Really* Moved: Chilean Quake Shifted a City 10 Feet to the West
The magnitude 8.8 earthquake that rocked Chile on February 27th didn’t just move the Earth’s axis, thereby shortening the day by 1.26 microseconds, but it also caused entire cities to shift their geographical location.
Studying precise GPS images of the area struck by the quake, a team led by earth scientist Mike Bevis discovered that the Chilean city of Concepción had moved 10 feet to the west. The epicenter of the quake was 71 miles northeast of Concepción, which is Chile’s second largest city.
The effect was widespread: The capital city, Santiago, was wrenched 11 inches west-southwest, while Beunos Aires, located nearly 800 miles from the epicenter, jumped an inch to the west. The earthquake was the fifth largest ever to be recorded by seismographs and even caused far-off areas like Fortaleza, Brazil and the Falkland Islands to change location slightly. The changes were detected by teams from The Ohio State University, the University of Hawaii, the University of Memphis and the California Institute of Technology, as well as agencies across South America [CNN].
The area where the quake hit is of particular interest to geoscientists because it is an active subduction zone, where an oceanic plate is colliding with a continental plate and being pushed into the Earth’s molten mantle below [Wired]. The world’s five largest quakes since 1900, including the largest quake ever recorded (a Chilean quake measuring 9.5), have all occurred in subduction zones. Earth scientist Ben Brooks of the University of Hawaii declared that this “earthquake will arguably become one of the, if not the most important, great earthquakes yet studied….We now have modern, precise instruments to evaluate this event” [CNN].
Image: University of Hawaii